Observation or lance door



Jan. 12, 1960 P. R. GROSSMAN ET AL OBSERVATION OR LANCE DOOR 2 Sheets-Sheet 1 Filed Dec. 30, 1955 FIG. 2

INVENTORS P aul R. Grossman h ys e0 W m m L N r u n e J H ATTORNEY Jan. 12, 1960 P. R. GROSSMAN ET AL 2,920,585

OBSERVATION OR LANCE DOOR Filed Dec. 30, 1955 2 Sheets-Sheet 2 INVENTORS Paul R.Grossman James L.Harvey Henry N. Dluehosh ATTORNEY United States Patent OBSERVATION OR LANCE DOOR Paul R. Grossman, James L. Harvey, and Henry N. Dluehosh, Alliance, Ohio, assignors to The Babcock & Wilgox Company, New York, N.Y., a corporation of New ersey Application December 30, 1955, Serial No. 556,559

7 Claims. (Cl. 110-179) The present invention relates in general to access means through which internal conditions in a chamber may be observed and internal wall and other heat transfer surfaces may be rendered accessible for inspection and cleaning.

More particularly, the invention relates to the construction of access and closure means especially adapted for use with furnaces or other similar closed chambered structures normally operating under internal gaseous pressures above atmospheric pressure. Structures suitable for the practice of our invention include, for example, boilers having a combustion chamber together Wtih a communicating gas space wherein the gases of combustion are utilized mainly for the generation and heating of vapor. In other suitable structures the high pressure gases may be produced for various other purposes such as utilization in processes or as a motive fluid for gas turbines.

In installations of the character described the chamber walls are often fluid cooled to provide protection from high gas temperatures and further are made gastight throughout to avoid the troublesome and dangerous condition resulting from the leakage of gases. When a wall opening is provided through which access may be had to the chamber interior for cleaning or inspection, it is essential that the opening be fitted with closure means suitably constructed and arranged so as to maintain the continuity of the gas-tight wall construction. Further, since it is necessary in many instances to gain access to the interior during normal furnace or chamber operation, provision must be made to prevent the discharge of the hot products of combustion when the closure means is moved to expose the opening.

In boiler construction, for example, wherein the outer enclosing walls are generally upright and rectangularly arranged, it has been customary to provide wall ports or openings in the planar side wall areas for the purpose of observing interior furnace or chamber conditions, or for removing slag accumulations from the various interior surfaces by means of a lance or other implement inserted through the opening. Each opening is fitted with a suitable access and closure means and, when provided in a planar wall area, generally results in an assembly which appreciably limits the angle of vision or observation and also the available lance working range through any one opening. Consequently, it has been necessary to provide a considerable number of such openings in each of the surrounding walls in order to permit observation of the chamber throughout at least the greater part of its cross-section, and to render interior wall and other heat transfer surfaces accessible for cleaning.

The present invention provides a wide angle access and closure structure adapted for use in a wall of a chamber normally confining gases under superatmospheric pressure whereby the lance working range and range of vision of internal chamber conditions are substantially increased. The access and closure structure comprises a frame arranged in a wall opening to form a passage 2,920,585 Patented Jan. 12, 1960 of the chamber to prevent discharge of gases when the outer end of the passage is uncovered for lancing or observation purposes.

The various features'of novelty which characterize our invention are pointed out with particularity in the claims annexed to and forming a part of this specification. For a better understanding of the invention, its operating advantages and specific objects attained by its use, reference should be had to the accompanying drawings and descriptive matter in which we have illustrated and described a preferred embodiment of our invention.

Of the drawings:

Fig. 1 is a front elevation of a chamber access and closure means constructed in accordance with our invention;

Fig. 2 is a plan section taken along line 22 of Fig. 1;

Fig. 3 is a plan section, similar to Fig. 2, showing a modification;

Fig. 4 is a sectional elevation taken along the line 4-4 of Fig. 1;

Fig. 5 is an enlarged fragmentary section taken along the line 5-5 of Fig. l; and

Fig. 6 is an enlarged fragmentary section showing the access passage and the relation of the frame parts defining the passage.

In the embodiment of the invention shown in the drawings the access means is arranged in cooperation with an opening 10 through a wall 11 of a chamber 12 normally operated to confine high temperature gases under superatmospheric pressure. The opening 10 is situated between vertically extending fluid cooled tubes 13 associated with the wall 11 and permits observation of interior chamber conditions or insertion of a lance or other implement to dislodge slag or other accumulations.

It should be understood that, except for a region including an opening such as 10, the wall tubes 13 are arranged vertically and in closely spaced parallel relationship throughout the major portions of their lengths. With the wall tubes so arranged, the opening 10 may be formed by displacing intermediate wall tube portions at and adjacent the desired opening location. The displacement of intermediate tube portions is effected by reverse bends. Tube 13a and the next adjacent tube 13c are reversely bent in planes at right angles to each other, thereby displacing a portion of the tube to the position 13d outwardly of its original position of planar alignment with the tubes 13. The tube 13a is formed with reverse bends in the plane of the tube row 13 and its intermediate portion moved to the space made available by the displacement of tube 13c. The wall tubes defining the opposite side of the opening 10 are similarly formed with reverse bends and their intermediate portions similarly displaced.

The wall 11 includes inner metal casing 14 suitably secured to the wall tubes 13, insulation 15 and outer metal casing 16 to provide with other walls of similar construction a completely sealed chamber permitting operation at high positive gas pressures.

The access means for the opening 10 includes an inner frame 17 having an interior passage 18 adapted to register with the opening 10. The passage 18 is of substam tially circular cross-section throughout its length and of substantially acute frusto-conical section converging inwardly from each end of the passage 18 to provide an intermediate throat portion; of restricted diameter. The inner frame: 17- comprises a, sleeve or inner section- 19 secured as by welding tov adjacent wall tubes; arelatively short throat section 20. arranged concentrically of and radiallyspaced. from theouter end of thefsleeve19'. and securedby. Welding toan outer frame 22; anan outer frusto-conical section21 extending from the outer end of vthe throatsection 20. The inner edges of the sleeve 19. and the throatsection 20 are beveled as at 19a and 20a.so as to formside segmentsof an. imaginary common substantially frusto-conical section having its vertex facing the throat. section 20. and the. sides adjacent its base. in. substantially, tangential relation to the tube portions 13b adjoinnig the opening 10.

Asshovwi in Fig. 6, the imaginaryapexes of the inner and. outer frusto-conical sections of thepassage 18 are disposed in overlapping,relationship. Theinner frame parts are proportioned and arranged so as to provide a wide angle of vision or lance working rangewithin the chamber. spective frusto-conical sections are preferably equal, a preferred angularity having been found to be about 70. Where the frusto-conical sections have apexangles of equal value, the proportioning of the inner frame parts may be; determined by-the formula w=msm where W is the perpendicular distance between the imaginary apex of one of the frusto-conical sections and the side surface of the other frusto-conical section or this distance may be called width of observation or the width of lance that can be accommodate at the maximum angle of access, D is the distance between the imaginary apexes', and A is the apex angle,

Where the frusto-conical sections have apex angles A, A whose values are diiferent, the proportioning of the inner frame parts may be determined by establishing the width of observation or width required to permit lance movement through an angle equal to the lesserof the apex angles of the frusto-conical sections. The width in this case is the perpendicular distance between the apex of the frusto-conical section having the smallest apex angle to an imaginary line drawn parallel to the side surface of that frusto-conical section and passing through the nearest point of the throat section to the apex of the smallest angle.

Although the preferred embodiment of our invention includes an access passage of substantially circular crosssection throughout its length and of substantially acute frusto-conical section at the inner and outer portions of the passage, means defining an accesspassage of rectangular cross-section throughout its length andof acute frusto-pyramidal section may be used and'what has been said with regard to the proportioning of the parts defining the passage also would be applicable in this instance. Further, while the apex angles of the-inner and outer sections of .the access passage are preferably equal and of a value of 70, apparatus constructed in accordance with our invention and providing access to the chamber interior through an angle from 50 to 100 would be suitable.

In order to prevent escape of hot gases and other products of combustion when the door is opened for lancing or observation purposes, provision is made for directing jets of high pressure air at high velocity into thepassage 18 in the'direction of the opening and preferably at an angle of 6 to the axis of the passage 18. For this purpose, a portion of the innerfrarne 17 is surroundedby the outer frame 22 extending axially of'the passage 18 from the outerend of the outer frustoconical section 21' to an intermediate portion of the To thisend, the apex angles A, A of there- 2,920,;sss

throat section 20 to define an air manifold 23. Circumferentially spaced angularlyv directed holes 24 are drilled at the juncture of the throat section 20 and the outer section 21 for the discharge of high velocity jets of air into the passage 18. Compressed air or other gaseous fluid under relatively high pressure is delivered to the manifold 23 through pipes 25 and 26, the supply of air being controlled by-a three-way valve 27.

Theouter endof the. outerframe 22.is.fo-rrned with a1 rectangular lateralflange 28 adjacent the outer face of the wall 11 and attached by cap screws to theouter casing 16. A plate 29 is secured by welding at one-end to the flange 28 and at the, other end to the wall tubes 13 in a gas-tight relation, and together with plates 30secured to tubes 1311, the flange 28, the frame 22 and portions of the wall tubes define a space which may be filled with moldable refractory.

A ring shaped yoke 31 is pivoted in a lug 32 on the outside of the flange28 and is connected by a pivot pin 33 to the lug 32; A circular door 34 formed with circumferentially spaced radial projections 35 and 36 is removably connected to the yoke 31 by support pins 37 extending through the yoke 31 into the radial projections 35 of the" door 34. The pins 37 are held in place by set screws 38. The door34 is also formed with a circular opening 39: which is in alignment with the passage 18 when-the door. is closed. The outer end of the opening 39 is, enlargedto form an annular recess for an observationwindow 40which: is held in placeby afianged ring 41 securedtothedoor 34by capscrews 42. A groove 43 is;formed:in the inner-face of the door 34-and filled with asbestos or other suitablepackingmaterial 44 to provide a gas-tight seal between the door 34 and the flange 28s-when the-door is closed.

A door latching mechanism is providedwhich includes aninverted U-shapedlug 45 on-the yoke 31 and a latch 46 associated 'with the flange 28. The latch 46 comprises a knob: 47 threaded on a stud 48 pivotally supported by means of a pinextending horizontally through spaced brackets 49 on the flange 28; The lug 45 is formed with a sidearm portion 50, which prevents opening of the door until after the air jets are inaction, and an outer arm portion 51, which provides a bearing surface or seat for the knob 47.

When the door is fully closed, as shown in-the drawings, the valve 27' is in position' to allow low-pressure cooling air to flow from a pipe 56 into the passage 18 in the manner previously described, and the door 34 is sealed against the flange 28 throughout the perimeter of the packing 44 through the force of the knob 47 bearing against the seat provided by the lug 45. Cap screws 52 extending through the yoke 31 and bearing against the outer face of "the radial projections 36 onthe door 34 permit adjustment of the space between the yoke 31. and the door 34 to assure that the packing material 44 in the door is sealed firmly'against the flange 28. Beforesuch adjustmentismade, the cap screws 38 must beloosened to allow axial movement of the yoke with relation to the door.

Movement of valve 27 is manually effected by a pivotally mounted handle 53 having an angle plate 54 secured atone end'and'interlocked with the lug side arm portion 50 to prevent opening of the door until after the valve 27 is rotated clockwise. After the valve is so rotated, high pressure compressed air is discharged into the passage 18, thereby preventing'th discharge of hot gases from the chamber 12 andpermitting lancing or other operations with safety through the uncovered passage 18.v

In order to return the door to its fully closed position, the foregoing operations are reversed, that is, the door is first'secured in its-closed position in the manner hereinbefore described and then the valve is rotated 90 counter-clockwise.

lnthemodifieation'shownin Fig; 3, arefractory-filled lance door 55 of substantially circular cross-section is mounted in place of the observation door 34. The lance door 55 is interchangeable with the observation door 34 simply by loosening the set screws 38, removing the pins 37, removing the observation door and substituting the lance door in its place, replacing the pins 37 and securing same by tightening the set screws 38.

While in accordance with the provisions of the statutes illustrated and described herein a specific form of the invention now known to us, those skilled in the art will understand that changes may be made in the form of the apparatus disclosed without departing from the spirit of the invention covered by our claims, and that certain features of the invention may sometimes be used to advantage without a corresponding use of other features.

What is claimed is:

1. In combination with a wall including contiguous fluid cooled tubes arranged in a row and providing a boundary for a chamber confining heating gases under superatmospheric pressure, means defining an opening in said wall comprising adjoining pairs of tubes of said row, each pair having laterally aligned intermediate offset portions formed by bends and disposed at the same side of said opening, a wide angle access structure arranged in said opening and comprising means forming a passage in the shape of two oppositely converging substantially frusto-conical inner and outer sections with an axially elongated cylindrical throat portion of restricted cross-section therebetween of substantially constant cross-sectional area, portions of said adjoining tubes being arranged to cool at least a portion of said access structure, said oppositely converging frusto-conical sections having their imaginary apexes arranged in overlapping relationship and their axes collinear, the apex angles of said convection frusto-conical sections being equal and in the range of 50 to 100, said access struc ture being proportioned and arranged to provide access to the interior of said chamber through an angle substantially equal to the apex angle, a door at the outer end of said passage in gas-tight relationship with said access structure, and means for introducing a high velocity gaseous fluid into said passage at the juncture of said outer section and said throat portion and in the direction of said chamber at a pressure sufficient to at least neutralize the chamber pressure when the door is to be opened for access and effecting a path of gaseous fluid travel through said throat and inner section substantially parallel to but in converging relation with the axis of said passage.

2. In combination with a wall including contiguous fluid cooled tubes arranged in a row and providing a boundary for a chamber confining heating gases under superatmospheric pressure, means defining an opening in said wall comprising adjoining pairs of tubes of said row, each pair having laterally aligned intermediate olfset portions formed by bends and disposed at the same side of said opening, a wide angle access structure ar ranged in said opening and comprising means forming a passage in the shape of two oppositely converging substantially frusto-conical inner and outer sections with an axially elongated cylindrical throat portion of restricted cross-section therebetween of substantially constant cross-sectional area, portions of said adjoining tubes being arranged to cool at least a portion of said access structure, said oppositely converging frusto-conical sections having their imaginary apexes arranged in overlapping relationship and their axes collinear, the apex angles of said converging sections being in the range of 50 to 100, said access structure being proportioned and arranged to provide access to the interior of said chamber through an angle substantially equal to the lesser of the two apex angles, a door at the outer end of said passage in gas-tight relationship with said access structure, and means for introducing a high velocity gaseous fluid into said passage at the juncture of said outer section and said throat portion and in the direction of said chamber at a pressure sufiicient to :at least neutralize the chamber pressure when the door is to be opened for access and effecting a path of gaseous fluid travel through said throat and inner section substantially parallel to but in converging relation with the axis of said passage.

3. In combination with a wall including contiguous fluid cooled tubes arranged in a row and providing a boundary for a chamber confining heating gases under superatmospheric pressure, means defining an opening in said wall comprising adjoining tubes of said row having intermediate offset portions formed by bends, a wide angle access structure arranged in said opening and comprising means forming a passage in the shape of two oppositely converging inner and outer sections with an axially elongated cylindrical throat portion of restricted cross-section therebetween of substantially constant crosssectional area, portions of said adjoining tubes being arranged to cool at least a portion of said access structure, said oppositely converging sections having their imaginary apexes arranged in overlapping relationship and their axes collinear, the apex of angles of said converging sections being equal and in the range of to 100, said access structure being proportioned and arranged to provide access to the interior of said chamber through an angle substantially equal to the apex angle, a door at the outer end of said passage in gas-tight relationship with said access structure, and means for introducing streams of high velocity air into said passage at the juncture of said outer section and said throat portion and in the direction of said chamber at a pressure sufiicient to at least neutralize the chamber pressure when the door is to be opened for access and effecting a path of air travel through said throat and inner section substantially parallel to but in converging relation with the axis of said passage, said last named means providing a flow of low velocity low pressure air into said passage to cool said access structure when the door is in its normally closed position.

4. In combination with a wall including contiguous fluid cooled tubes arranged in a row and providing a boundary for a chamber confining heating gases under superatmospheric pressure, means defining an opening in said wall comprising adjoining pairs of tubes of said row, each pair having laterally aligned intermediate offset portions formed by bends and disposed at the same side of said opening, a wide angle access structure arranged in said opening and comprising means forming a passage in the shape of two oppositely converging inner and outer sections with an axially elongated cylindrical throat portion of restricted cross-section therebetween of substantlally constant cross-sectional area, portions of said adoining tubes being arranged to cool at least a portion of said access structure, said oppositely converging sections 4 having their imaginary apexes arranged in overlapping relationship and their axes collinear, the apex angles of said converging sections being in the range of 50 to said access structure being proportioned and arranged to provide access to the interior of said chamber through an angle substantially equal to the lesser of the two apex angles, a door at the outer end of said passage in gastight relationship with said access structure, and means for introducing streams of high velocity air into said passage at the juncture of said outer section and said throat portion and in the direction of said chamber at a pressure suflicient to at least neutralize the chamber pressure when the door is to be opened for access and effecting a path of air travel through said throat and inner section substantially parallel to but in converging relation with the axis of said passage, said last named means providing a flow of low velocity low pressure air into said passage to cool said access structure when the door is in its normally closed position.

5. In combination with a wall including contiguous fluid cooled tubes arranged in a row and providing a boundary for a chamber confining heating gases under superatmosphericpressure, meansdefining an opening in said-wall comprising adjoining pairs of'tubes'of said row, each pair having laterally aligned intermediate oflset portions formedby bends andjdisposed at the same side of said opening, a wide angle access structure arranged in said opening and comprising means forming-a passage in the shape ofoppositely convergingisubstantially frustoconicalinner'and outer sections with an axially elongated throat portion of restricted cross-section therebetween of substantially constant cross-sectional area, portions of said adjoining; tubes being arranged to cool at least a portion of said access structure, said oppositely convergingfrusto-conical' sections having their imaginary apexes arranged in overlapping relationship andtheir axis collinear, the'apex angles of said converging sections being equal and in the range of 50 to 100, said access structure'beingproportionedand' arranged to provide access to-theinterior of said chamber through an angle substantially-equal'to'the apex angle; a door at the outer end of said passage in gas-tight relationship with said access structure, means includingcircumferentially spaced ports between said outer section and throat for introducing i streams of high velocity'air into'said passage at the juncture of said outer section-and said throat portion and in the direction ofsaid chamber at a pressure sulficient to atleast neutralize the chamber pressure when the door is to be opened for access and efiectinga path ofrair travel through said throat and inner section substantially parallel to but in converging relation with the axis of said passage, saidlast named means providing a flow of low velocity low pressure air into said passage to cool said access structure when the door is in its normally closed position, and means arranged to prevent opening of said door until said high-velocity pressure neutralizingairis directed into said passage.

6. In combination with awall including fluid cooled tubes arranged in a row and providing'a boundary' for a chamber confining heating gases under superatmospheric pressure, means definingan opening in said wall, a wide angle access structure arranged in said opening and comprising means forming a passage in the shape of two oppositely converging inner and outer sections with an axially elongated throat portion of restricted cross-section therebetweenof substantially constant crosssectional area, said oppositely converging sections having their imaginary apexes arranged in overlapping relationship-and-their axescollinear, the apex-angles of said convergingsections being equal and in the range of to said access structurebeing proportioned and arranged to provide access to the interior of said chamber through an angle substantially equal to the apex angle, a door atthe outer end of said passage in gastight relationship with said access structure, and means for introducing a high velocity gaseous 'fluid into said passage at the juncture of said outer section andsaid throat portion and in the direction ofsaid" chamber at a pressure sufiicient to at least neutralize the chamber pres sure when the door is to be opened for access and eifect ing a path of gaseous fluid travel through said throat and inner section substantially parallel to but in converging relation with the axis of said passage.

7. In combination with a wall includingfiuid' cooled tubes arranged in a row and providing a boundary for a chamber confining heating gases under 'superatmospheric pressure, means defining an opening in said wall; a Wide angle access structure arranged in said opening and comprising means forming a passage in the shape of two oppositely converging inner and outer sections with an axially elongated throat portion of restricted cross-section therebetween of substantially constant cross sectional area, said oppositely converging sections having their imaginary apexes arranged in overlapping relationship and theiraxes collinear, the apexangles of said converging sections being in the range of '50 to 100 said access structure being proportioned and arranged-to provide access to the interior of said chamber through an angle substantially equal to the lesser of the two apex angles, a door at the outer end of saidpassage in gas tight relationship with saidaccess structure, and. means for introducing a high velocity gaseous fluid into said passage at'the juncture of said outer section and said throat portion and in the direction of said. chamber at a pressure sufiicient to at least neutralize the chamber pres sure when the door is to be opened for access and effecting a path'of gaseous fluid travel through said1throat and inner section substantially parallel to but in converging relation with the axis of said passage.

References Cited in thetfile of this patentv UNITED STATES PATENTS 13,873 Gilman Dec. 4, 1855 2,105,309 Carleton Jan. 11, 1938 2,545,886 Kooistra Q. Mar. 20, 1951 2,704,999 Schoessow Mar. 29 1955 

